However, automatically inferring discourse structure is challenging which
hinders wider application [1]}. At its root lies the issue of data annotation:
popular coherence formalisms like the Rhetorical Structure Theory (RST, [2]}, Segmented Discourse Representation Theory (SDRT, [3]}, and the Penn Discourse Treebank (PDTB, [4]} require
experts—typically linguists trained for the task—to reason through long documents over large relation taxonomies. These features, coupled with the difficulties of annotating full structures in the case of RST and SDRT, make the task inaccessible to lay annotators. The taxonomies differ across formalisms [5]}, and their coverage and definitions are being actively researched and refined [6]}, [7]}, [8]}.
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